Aquifer injection is being identified as an option for the management of coal seam gas (CSG) water in Queensland. The feasibility of aquifer injection will depend on a number of issues, including the ability to manage any potential risks to the environbmental, economic and social values of the receiving aquifers. A hydrogeochemical assessment to assess the compatibility of re-injection of pure reverse osmosis (RO) permeate and RO permeate/CSG water blends into different target aquifers forms part of the approvals process.